Where do I see log entries in Application Insights?
I have tested Microsoft.ApplicationInsights.NLogTarget on my local and get the trace information in Application Insights. We can get this information via click Your Application insigths -> Overview -> Search, like the following screenshot.
For how to use Nlog in Application Insights, please read this article.
Technically if you add some another logger package for AI, new kind of appender is added. Internally the appender calls Telemetry methods from Application Insights and add some additional information to request or exception (using the AI properties).
The answer is: You can find all your telemetries on one place in the Azure portal as usual. For example in Diagnostics Search or in the aggregated graphs with a small delay.